Adding support for closure compiler and some documentation

in the README about how to use it.


git-svn-id: http://svn.openlayers.org/trunk/openlayers@11448 dc9f47b5-9b13-0410-9fdd-eb0c1a62fdaf

build/README.txt

@@ -1,14 +1,43 @@
+The OpenLayers build tool supports several different
+forms of compressing your javascript code, and a method
+of describing build profiles to create customized 
+OpenLayers builds with only the components you need.
 
-## HowTo: Build & deploy "Shrunk" Single File Library version of OpenLayers ##
+When building a file, you can choose to build with several
+different compression options to the Python-based build.py
+script. The following is an example script:
 
- * Build:
+python build.py -c closure full OpenLayers-closure.js
 
-     cd build
-     ./build.py
-     cd ..
+This script selects the 'closure' compression mechanism,
+uses a config file called 'full.cfg', and writes the output
+to OpenLayers-closure.js.
 
- * Upload the result to the server: e.g.
+The options available for compression are:
 
-  scp build/OpenLayers.js openlayers@openlayers.org:openlayers.org/htdocs/code/
+ * closure
+   This requires you to have a closure-compiler.jar in your
+   tools directory. You can do this by fetching the compiler
+   from:
 
+     http://closure-compiler.googlecode.com/files/compiler-latest.zip
+
+   Then unzipping that file, and placing compiler.jar into tools
+   and renaming it closure-compiler.jar.
+
+ * closure_ws
+   This uses the closure compiler webservice. This will only work
+   for files source Javascript files which are under 1MB. (Note that
+   the default OpenLayers full build is not under 1MB.)
+
+ * jsmin
+   jsmin is the default compiler, and uses the Python-based
+   jsmin script to compress the Javascript. 
+
+ * minimize
+   This is a simple whitespace removing Python script, designed
+   to fill in when other tools are unavailable.
+
+ * none
+   None will leave the Javascript uncompressed.
 

build/build.py

@@ -12,6 +12,11 @@ def build(config_file = None, output_file = None, options = None):
         have_compressor.append("jsmin")
     except ImportError:
         print "No jsmin"
+    try:
+        import closure
+        have_compressor.append("closure")
+    except ImportError, E:
+        print "No closure (%s) % E"
     try:
         import closure_ws
         have_compressor.append("closure_ws")
@@ -51,6 +56,8 @@ def build(config_file = None, output_file = None, options = None):
         minimized = minimize.minimize(merged)
     elif use_compressor == "closure_ws":
         minimized = closure_ws.minimize(merged)      
+    elif use_compressor == "closure":
+        minimized = closure.minimize(merged)      
     else: # fallback
         minimized = merged 
     print "Adding license file."

tools/closure.py

@@ -0,0 +1,21 @@
+import sys
+import os
+import tempfile
+
+path = os.path.join(os.path.dirname(__file__), "closure-compiler.jar")
+if not os.path.exists(path):
+    raise Exception("No closure-compiler.jar at %s; read README.txt!" % path)
+
+def minimize(code):
+    ntf = tempfile.NamedTemporaryFile()
+    ntf.write(code)
+    ntf.flush()
+
+    ntf2 = tempfile.NamedTemporaryFile()
+
+    os.system("java -jar %s --js %s --js_output_file %s" % (path, ntf.name, ntf2.name))
+    ntf2.seek(0)
+    data = ntf2.read()
+    ntf.close()
+    ntf2.close()
+    return data

tools/closure_ws.py

@@ -22,5 +22,7 @@ def minimize(code):
     response = conn.getresponse()
     data = response.read()
     conn.close()
-    print "%.3f seconds to compile", time.time() - t 
+    if data.startswith("Error"):
+        raise Exception(data)
+    print "%.3f seconds to compile" % (time.time() - t) 
     return data